Characterization of Methane Excess and Absolute Adsorption in Various Clay Nanopores from Molecular Simulation.
Characterization of Methane Excess and Absolute Adsorption in Various Clay Nanopores from Molecular Simulation.
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DOI：
10.1038/s41598-017-12123-x
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发表时间：
2017-09-20
影响因子：
4.6
通讯作者：
Jin Z
中科院分区：
文献类型：
--
作者：
Tian Y;Yan C;Jin Z
在这项工作中，我们使用巨正则蒙特卡罗（GCMC）模拟研究甲烷在各种粘土纳米孔中的吸附，并分析不同的方法来表征绝对吸附。作为页岩的重要组成部分，粘土矿物可以具有大量的纳米孔隙，这极大地有助于页岩中的天然气地质储量。在以往的工作中，绝对吸附量通常是由过量吸附量和松质酸盐的体积液相密度来计算的。结果表明，在80 MPa以下，甲烷吸附相密度随压力的增加而增加.即使用GCMC更新的吸附相密度，绝对吸附计算也存在显著误差。因此，我们建议使用过量吸附和吸附相体积来计算绝对吸附，并在高压条件下将差异减小到小于3%。我们还发现，超临界Dubininin-Radushkevich（SDR）的拟合方法，这是常用的实验中转换的过量吸附绝对吸附可能没有坚实的物理基础，甲烷吸附。不同粘土矿物的甲烷过剩量和单位比表面积的绝对吸附量相似，与前人的实验数据一致。在中孔中，单位比表面积的过量吸附和绝对吸附对孔径不敏感。我们的工作应该提供重要的基本认识和见解，以准确估计页岩储层中的天然气地质储量。
In this work, we use grand canonical Monte Carlo (GCMC) simulation to study methane adsorption in various clay nanopores and analyze different approaches to characterize the absolute adsorption. As an important constituent of shale, clay minerals can have significant amount of nanopores, which greatly contribute to the gas-in-place in shale. In previous works, absolute adsorption is often calculated from the excess adsorption and bulk liquid phase density of absorbate. We find that methane adsorbed phase density keeps increasing with pressure up to 80 MPa. Even with updated adsorbed phase density from GCMC, there is a significant error in absolute adsorption calculation. Thus, we propose to use the excess adsorption and adsorbed phase volume to calculate absolute adsorption and reduce the discrepancy to less than 3% at high pressure conditions. We also find that the supercritical Dubinin-Radushkevich (SDR) fitting method which is commonly used in experiments to convert the excess adsorption to absolute adsorption may not have a solid physical foundation for methane adsorption. The methane excess and absolute adsorptions per specific surface area are similar for different clay minerals in line with previous experimental data. In mesopores, the excess and absolute adsorptions per specific surface area become insensitive to pore size. Our work should provide important fundamental understandings and insights into accurate estimation of gas-in-place in shale reservoirs.
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DOI：
10.1021/i160011a009
发表时间：
1964-01-01
期刊：
INDUSTRIAL & ENGINEERING CHEMISTRY FUNDAMENTALS
影响因子：
--
作者：
GRANT, RJ;MANES, M
通讯作者：
MANES, M
影响因子：
--
作者：
Labani, Mohammad Mandi;Rezaee, Reza;Al Hinai, Adnan
通讯作者：
Al Hinai, Adnan
影响因子：
2.2
作者：
BISH, DL;VONDREELE, RB
通讯作者：
VONDREELE, RB
影响因子：
10.9
作者：
Do, DD;Do, HD
通讯作者：
Do, HD
影响因子：
10.9
作者：
Gensterblum, Y.;van Hemert, P.;Wolf, K. -H. A. A.
通讯作者：
Wolf, K. -H. A. A.